Former Rep. Joe Sestak, who lost to now-Sen. Pat Toomey in Pennsylvania in 2010, is already gearing up for a rematch.

The former Philadelphia-area congressman announced Tuesday in an email to supporters and a video on his website that he’s launching an exploratory committee for Senate in 2016 to challenge Toomey again.

“[T]he leadership in America is not exceptional right now, and most damaging to our nation’s purpose is the U.S. Senate’s lack of leadership and lack of accountability as our nation careens from crisis to crisis,” he said in the email. “Its failure has paralyzed the governing of our nation, even affecting how well state and local leaders can serve the people.”

“I want to begin that change, starting right here in Pennsylvania,” he continued. “The Senate needs an independent leader accountable only to “We the People,” not any other interests…a leader accountable for deeds, not intentions.”

Sestak raised suspicions that he was planning a run for statewide office when he raised $460,000 in the first quarter of this year. He’d also been seen as a top contender for governor to challenge vulnerable incumbent Gov. Tom Corbett next year, and insiders in the state say he’d been considering both governor and Senate.

His announcement — far earlier than most Senate prospects reveal their plans — comes a day after the Pennsylvania Republican Party had filed a Federal Elections Commission complaint against him, saying he was violating campaign finance law by raising so much campaign cash without specifying which office it was for.

Sestak lost to Toomey by just 2 points in a year that brought sweeping victories for Republicans across the country and across Pennsylvania.

But Toomey’s popularity in the state has jumped considerably following his efforts to sponsor and advocate for the background checks compromise in the Senate, making him a more formidable opponent in his reelection bid. A Quinnipiac poll last month found his approval rating at 48 percent, compared with 30 percent who disapprove — an increase from his previous 43-32 approval rating among the state’s voters in March.